1. Field of the Invention
This invention is believed to be found in the field of dispensing, and more particularly in the field of dispensing of a gas or vapor.
Gas accumulators and blaster apparatus are known in the prior art. This type of apparatus is adapted for mounting to the side of a storage bin, in which granular materials are kept The function of a gas accumulator and blaster apparatus is to dislodge any of the granular material which has become blocked or bridged within the storage bin. Some of the known prior art includes U.S. Pat. No. 3,915,339 as issued to Matson on Oct. 28, 1975; U.S. Pat. No. 3,788,527 as issued to Matson on Jan. 29, 1974; U.S. Pat. No. 4,197,966 as issued to the present applicant on Jul. 15, 1980; U.S. Pat. No. 4,469,247 as issued to Tompkins on Sep. 04, 1984; U.S. Pat. No. 4,676,402 as issued to Stetson on Jun. 30, 1987; U.S. Pat. No. 4,703,869 as issued to De Rooy on Nov. 3, 1987; U.S. Pat. No. 4,767,024 as issued to Rappen on Aug. 30, 1988; U.S. Pat. No. 4,819,821 as issued to Simoens on Apr. 4, 1989; and U.S. Pat. No. 4,440,147 as issued to Tolan on Nov. 14, 1989.
The above listed known prior art patents show or disclose a piston member which is used to control the direction of flow of a gas or vapor which has been collected under pressure in a tank. Many of these patents disclose peripheral sealing means between the piston and its associated cylinder wall. Many of the prior art systems use spring means to urge the piston to a closed condition.
Peripheral seals between the piston and the wall of the cylinder increase the forces necessary to move the piston from an open to a closed position. This force may be referred to as a "break away force". The employment of a spring also adds to these "break away forces". It has been found that valuable time is lost in opening and closing the valve when peripheral seals and/or springs are used. Any delay in the closing of the valve, after all the pressurized gas is expelled from the tank, may allow dust from the storage bin to contaminate the piston, the seal, and/or the cylinder wall. Any contamination of these items will not only increase the opening or closing times of the blaster but can cause unwanted leakage of gas.
It has also been found that known blaster apparatus utilizing a piston type valve require that the piston and its associated cylinder be machined and matched in pairs to provide the desired smooth operation.
The present invention is believed to overcome some of the known problems which have been identified above by using (1) a movable piston which does not use a peripheral seal; (2) gravity is used to immediately close the valve member when pressure has dropped substantially to atmosphere; (3) containment of any undesirable particles which may be carried in the feeding air line. There is also a need to provide a low cost system which will fit interior of standard tubing or pipe.